Firefox Issue on Pop!_OS and Ubuntu 19.10

I'm running Ubuntu 18.4 on my Galago Pro Laptop, with Firefox Quantum 68.7 installed. Works great except that videos, and gifs don't play on all websites except You Tube.

The problem I'm having is with Pop!_OS 19.10 and Ubuntu 19.10. Both OS's install Firefox 75 and both OS's have the same problem, in that neither will play videos or gifs. However I installed Opera and it works perfectly, so I don't think it's an OS problem.

Any ideas?

Last edited by stephanie-s; April 17th, 2020 at 01:17 PM.
Reason: Update of issue